1. Field of the Invention
The present invention relates to a liquid crystal display device.
2. Description of the Related Art
In recent years, liquid crystal display devices have been broadly used in various applications taking advantage of their thin-profile and light weight, low voltage drive, low power consumption and so on. Display characteristics comparable to those of CRT are realized in the liquid crystal display devices, so that they have been used for application such as monitors and televisions for which CRTs are conventionally mainly used.
The liquid crystal display devices have been improved in terms of upsizing, gray-scale display, and high contrast to be used as monitors of computers or image display devices of televisions. In such applications, it is necessary that the liquid crystal display device can be viewed from any direction.
As a technology for realizing this wide viewing angle, an MVA (Multi-domain Vertical Alignment) mode liquid crystal display device is proposed from Fujitsu Co., Ltd.
A configuration of a basic principle of the MVA-mode liquid crystal display device is shown in FIGS. 2A and 2B. FIG. 2A shows the liquid crystal display device where no voltage is applied between substrates 201 and 202, and FIG. 2B shows the liquid crystal display device where a voltage is applied between the substrates 201 and 202. The substrate 201 is provided with protrusions 203, and the substrate 202 is provided with a protrusion 204. In FIG. 2A, liquid crystal molecules 212 are vertically aligned, and liquid crystal molecules 211 near the protrusions 203 and 204 are aligned with a tilt. In FIG. 2B, liquid crystal molecules 221 are aligned in accordance with the direction of electric fields. In other words, the liquid crystal molecules are vertically aligned where no voltage is applied thereto, and when a voltage is applied, the liquid crystal molecules tilt in four directions separately in four regions respectively. As a result of mixture of visual angle characteristics in the respective regions, a wide viewing angle can be obtained.
Fujitsu Co., Ltd. applied for the technology of further improving the visual angle characteristics of the MVA-mode liquid crystal display device (for example, Japanese Patent Laid-Open No. Hei 10-153782), and the technology of improving the display brightness (Japanese Patent Application No. 2001-106283).
It is desired to realize a wider viewing angle in the liquid crystal display device. Further, a liquid crystal display device with high brightness is desired. Furthermore, a liquid crystal display device having both a wide viewing angle and high brightness is desired.